Pfizer Inc. announced final results from a randomized phase 3 trial of Sutent (sunitinib malate) in patients with advanced pancreatic neuroendocrine tumours, a type of cancer which originates in the hormone-producing area of the pancreas. Sunitinib more than doubled the time patients with pancreatic neuroendocrine tumours lived without disease progression compared with patients treated with placebo, according to study findings presented at the American Society of Clinical Oncology Gastrointestinal Cancers Symposium in Orlando, Florida.

An independent Data Monitoring Committee (DMC) recommended halting the trial in February 2009 because sunitinib showed significant benefit and the primary endpoint was met.

"This trial advances our understanding of the use of novel targeted therapies in a patient population with limited treatment options," said Dr. Mace Rothenberg, senior vice president of clinical development and medical affairs for Pfizer’s Oncology Business Unit. "We are pleased to be working toward filling an unmet patient need, as we did with Sutent four years ago in patients with kidney cancer and gastrointestinal stromal tumours."

The phase 3 study findings served as the basis for the recent filings of supplemental applications for sunitinib in the treatment of pancreatic neuroendocrine tumours with the regulatory authorities in the US, Europe and Canada.

This international, phase 3 trial compared sunitinib with placebo in patients with progressive, well-differentiated, malignant pancreatic neuroendocrine tumours. Patients were randomized to either the sunitinib (n=86) (37.5 mg/day, continuous daily dosing) plus best supportive care arm or the placebo plus best supportive care arm (n=85).

Results showed that median progression-free survival (PFS) was 11.4 months in patients treated with sunitinib compared with 5.5 months in patients treated in the placebo arm (Hazard ratio 0.418, p<0.001). Sutent also prolonged overall survival, a secondary endpoint of the trial (Hazard ratio 0.409, p=0.0204).

“The magnitude of Sutent’s benefit in the pancreatic neuroendocrine tumour patient population was an encouraging finding,” said Dr. Eric Raymond, professor of medical oncology and head of University Department of Medical Oncology (Service Inter Hospitalier de Cancerologie) Bichat-Beaujon, Clichy, France, and lead investigator on this sunitinib Phase 3 study. “These findings offer hope to a patient population for whom there are limited treatment options.”

Adverse events were similar to those observed in other sunitinib studies. The most commonly reported grade 3-4 adverse events in the sunitinib arm were neutropenia (12 per cent), hypertension (9.6 per cent), hand-foot syndrome (6 per cent), leukopenia (6 per cent) abdominal pain (4.8 per cent), diarrhoea (4.8 per cent), asthenia (4.8 per cent), fatigue (4.8 per cent) and hypoglycaemia (4.8 per cent). Grade 5 cardiac failure was experienced by 1.2 percent of the patients in the sunitinib arm.

Tumours of the neuroendocrine system are typically classified into two distinct categories: carcinoids or pancreatic neuroendocrine tumours. Pancreatic neuroendocrine tumours form in the endocrine (hormone-producing) tissues of the pancreas and are separate from exocrine tumours, which account for about 95 per cent of all pancreatic cancers.

Pancreatic neuroendocrine tumours are fairly rare, and reported in two to four people per million annually worldwide. Subtypes include insulinomas, glucagonomas and gastrinomas. Current treatment options are limited.

Sutent is an oral multi-kinase inhibitor approved for the treatment of advanced / metastatic renal cell carcinoma (RCC) and the treatment of gastrointestinal stromal tumourr (GIST) after disease progression on or intolerance to imatinib mesylate. To date, approximately 82,000 patients globally have been treated with sunitinib in the clinical setting and trials.

Sutent works by blocking multiple molecular targets implicated in the growth, proliferation and spread of cancer. Two important Sutent targets, vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), are expressed by many types of solid tumours and are thought to play a crucial role in angiogenesis, the process by which tumours acquire blood vessels, oxygen and nutrients needed for growth. Sutent also inhibits other targets important to tumour growth, including KIT, FLT3 and RET.